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• Adding total duration information in mp4 audio stream file with FFMPEG

  6 avril 2016, par lex82

  I’m trying to write an AAC audio stream into an mp4 file using the FFMPEG libraries. I am using a custom IO context that writes directly to a socket so I have to set ioContext->seekable = 0. To make this work I had to add the "movflags" empty_moov and frag_keyframe when writing the header.

  After writing the output to a file on the other end of the socket, I can play the file in VLC or Windows Media Player. However, seeking to a specific position in the file is not working properly in both players. WMP also does not show the total duration and VLC only flashes it shortly when reaching the end of the audio.

  Is there a way to add more metadata when muxing so the players are able to treat the file as if it was not written as a stream ? Transfer via the socket is not interrupted abruptly, so I could write metadata at the end of the file. I also know the total duration in advance, so I could add it to the header of the file if it was possible. I cannot use the faststart flag because this would require output to a seekable file before writing to the socket.

  Update : Tried setting nb_frames and avg_frame_rate on the stream but it didn’t help.

• How to convert raw H.264 stream from video call to mp4 file

  13 février 2020, par Daniel

  I have captured a SIP point to point video call using wireshark and I used the program ’videosnarf’ on Ubuntu 12.04 to extract the raw H.264 stream from the PCAP. I am having some problems with ffmpeg when trying to convert it to MP4. Below is the ffprobe output :

  [STREAM]
  
  index=0
  
  codec_name=h264
  
  codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
  
  codec_type=video
  
  codec_time_base=1/2400000
  
  codec_tag_string=[0][0][0][0]
  
  codec_tag=0x0000
  
  width=704
  
  height=396
  
  has_b_frames=0
  
  sample_aspect_ratio=1:1
  
  display_aspect_ratio=16:9
  
  pix_fmt=yuv420p
  
  level=51
  
  r_frame_rate=25/1
  
  avg_frame_rate=25/1
  
  time_base=1/1200000
  
  start_time=N/A
  
  duration=N/A
  
  [/STREAM]

  Here is the command I used to generate the MP4 :

  ffmpeg -f h264 -i H264-media-3.264 -vcodec copy output.mp4

  When I transfer the file to my Windows PC, I can’t open the file in VLC. When opening in Windows Media Player (not sure the version but it’s on Windows 8) it plays but very quickly (almost as if it’s playing in fast forward. I also tried with :

  ffmpeg -f h264 -i H264-media-3.264 -vcodec copy -r 25 output.mp4

  I am able to play the raw H.264 stream using "MPC-HC" on Windows but I need it in MP4 format.

• How to convert raw H.264 stream from video call to mp4 file

  30 mars 2015, par Daniel

  I have captured a SIP point to point video call using wireshark and I used the program ’videosnarf’ on Ubuntu 12.04 to extract the raw H.264 stream from the PCAP. I am having some problems with ffmpeg when trying to convert it to MP4. Below is the ffprobe output :

  [STREAM]
  
  index=0
  
  codec_name=h264
  
  codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
  
  codec_type=video
  
  codec_time_base=1/2400000
  
  codec_tag_string=[0][0][0][0]
  
  codec_tag=0x0000
  
  width=704
  
  height=396
  
  has_b_frames=0
  
  sample_aspect_ratio=1:1
  
  display_aspect_ratio=16:9
  
  pix_fmt=yuv420p
  
  level=51
  
  r_frame_rate=25/1
  
  avg_frame_rate=25/1
  
  time_base=1/1200000
  
  start_time=N/A
  
  duration=N/A
  
  [/STREAM]

  Here is the command I used to generate the MP4 :

  ffmpeg -f h264 -i H264-media-3.264 -vcodec copy output.mp4

  When I transfer the file to my Windows PC, I can’t open the file in VLC. When opening in Windows Media Player (not sure the version but it’s on Windows 8) it plays but very quickly (almost as if it’s playing in fast forward. I also tried with :

  ffmpeg -f h264 -i H264-media-3.264 -vcodec copy -r 25 output.mp4

  I am able to play the raw H.264 stream using "MPC-HC" on Windows but I need it in MP4 format.